Head Gasket Thickness

So I’m finally biting the bullet and planning to put in a APEX’I HG since the motor is apart, but my questions is what is the actual stock thickness? I’ve been trying to research but I’ve seen mixed answers on SON240, NICO, and other forums. It pretty much comes down to 0.8mm and 1.1mm, which is the actual size?

What does it matter?

Just want to know the info before I get my HG, if stock is 0.8mm I’d opt for a 1.1mm, if 1.1mm I’d opt for 1.5mm.